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| author | Nicolin Chen <nicoleotsuka@gmail.com> | 2020-09-02 01:16:45 +0300 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2020-09-03 19:12:15 +0300 |
| commit | 1e9d90dbed120ec98517428ffff4dacd9797e39d (patch) | |
| tree | d743be6b54427bb62e36e6d1ae2f6fc243cd70b7 /arch/sparc | |
| parent | 2281f797f5524abb8fff66bf8540b4f4687332a2 (diff) | |
| download | linux-1e9d90dbed120ec98517428ffff4dacd9797e39d.tar.xz | |
dma-mapping: introduce dma_get_seg_boundary_nr_pages()
We found that callers of dma_get_seg_boundary mostly do an ALIGN
with page mask and then do a page shift to get number of pages:
ALIGN(boundary + 1, 1 << shift) >> shift
However, the boundary might be as large as ULONG_MAX, which means
that a device has no specific boundary limit. So either "+ 1" or
passing it to ALIGN() would potentially overflow.
According to kernel defines:
#define ALIGN_MASK(x, mask) (((x) + (mask)) & ~(mask))
#define ALIGN(x, a) ALIGN_MASK(x, (typeof(x))(a) - 1)
We can simplify the logic here into a helper function doing:
ALIGN(boundary + 1, 1 << shift) >> shift
= ALIGN_MASK(b + 1, (1 << s) - 1) >> s
= {[b + 1 + (1 << s) - 1] & ~[(1 << s) - 1]} >> s
= [b + 1 + (1 << s) - 1] >> s
= [b + (1 << s)] >> s
= (b >> s) + 1
This patch introduces and applies dma_get_seg_boundary_nr_pages()
as an overflow-free helper for the dma_get_seg_boundary() callers
to get numbers of pages. It also takes care of the NULL dev case
for non-DMA API callers.
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
Acked-by: Niklas Schnelle <schnelle@linux.ibm.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'arch/sparc')
| -rw-r--r-- | arch/sparc/kernel/iommu-common.c | 10 | ||||
| -rw-r--r-- | arch/sparc/kernel/iommu.c | 3 | ||||
| -rw-r--r-- | arch/sparc/kernel/pci_sun4v.c | 3 |
3 files changed, 5 insertions, 11 deletions
diff --git a/arch/sparc/kernel/iommu-common.c b/arch/sparc/kernel/iommu-common.c index 59cb16691322..23ca75f09277 100644 --- a/arch/sparc/kernel/iommu-common.c +++ b/arch/sparc/kernel/iommu-common.c @@ -166,13 +166,6 @@ unsigned long iommu_tbl_range_alloc(struct device *dev, } } - if (dev) - boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1, - 1 << iommu->table_shift); - else - boundary_size = ALIGN(1ULL << 32, 1 << iommu->table_shift); - - boundary_size = boundary_size >> iommu->table_shift; /* * if the skip_span_boundary_check had been set during init, we set * things up so that iommu_is_span_boundary() merely checks if the @@ -181,6 +174,9 @@ unsigned long iommu_tbl_range_alloc(struct device *dev, if ((iommu->flags & IOMMU_NO_SPAN_BOUND) != 0) { shift = 0; boundary_size = iommu->poolsize * iommu->nr_pools; + } else { + boundary_size = dma_get_seg_boundary_nr_pages(dev, + iommu->table_shift); } n = iommu_area_alloc(iommu->map, limit, start, npages, shift, boundary_size, align_mask); diff --git a/arch/sparc/kernel/iommu.c b/arch/sparc/kernel/iommu.c index 4ae7388b1bff..c3e4e2df26a8 100644 --- a/arch/sparc/kernel/iommu.c +++ b/arch/sparc/kernel/iommu.c @@ -472,8 +472,7 @@ static int dma_4u_map_sg(struct device *dev, struct scatterlist *sglist, outs->dma_length = 0; max_seg_size = dma_get_max_seg_size(dev); - seg_boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1, - IO_PAGE_SIZE) >> IO_PAGE_SHIFT; + seg_boundary_size = dma_get_seg_boundary_nr_pages(dev, IO_PAGE_SHIFT); base_shift = iommu->tbl.table_map_base >> IO_PAGE_SHIFT; for_each_sg(sglist, s, nelems, i) { unsigned long paddr, npages, entry, out_entry = 0, slen; diff --git a/arch/sparc/kernel/pci_sun4v.c b/arch/sparc/kernel/pci_sun4v.c index 14b93c5564e3..6b92dd51c002 100644 --- a/arch/sparc/kernel/pci_sun4v.c +++ b/arch/sparc/kernel/pci_sun4v.c @@ -508,8 +508,7 @@ static int dma_4v_map_sg(struct device *dev, struct scatterlist *sglist, iommu_batch_start(dev, prot, ~0UL); max_seg_size = dma_get_max_seg_size(dev); - seg_boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1, - IO_PAGE_SIZE) >> IO_PAGE_SHIFT; + seg_boundary_size = dma_get_seg_boundary_nr_pages(dev, IO_PAGE_SHIFT); mask = *dev->dma_mask; if (!iommu_use_atu(iommu, mask)) |